This invention relates to spring units and in particular to a method and apparatus for producing such spring units.
In our co-pending International Patent Application No PCT/GB 97/01759 there are disclosed spring units comprising inner and outer springs for use in mattresses, beds, divan beds, and other upholstered units. The spring units disclosed in said co-pending patent application are pocketted spring units in which either the outer spring or the inner spring, or both the outer spring and the inner spring, is (are) enclosed in a covering or pocket of material so as to form the spring unit, and the present invention relates to a method and apparatus for making the spring units disclosed in said co-pending patent application. Spring units comprising an inner spring and an outer spring are knownxe2x80x94see for example United Kingdom Patent No 235,481. In said United Kingdom Patent No 235,481 there is disclosed a spring unit comprising an inner pocketted spring and an outer spring surrounding said pocketted spring, but because of the format of the spring unit, the method and apparatus for the production of the spring unit are not thought suitable for the production of the spring units disclosed in our said co-pending patent application.
According to one aspect of the present invention there is provided a method for the production of a spring unit for use in a mattress, bed, divan bed, or other upholstered unit, the method including the steps of positioning a second spring in readiness for insertion into a first spring, feeding said first spring from a supply source immediately after said second spring is positioned in readiness for insertion into said first spring, positioning said second spring within said first spring, and forming said first spring into a pocketted spring.
The method may include the steps of feeding said first spring from a spring supply source immediately after said second spring is positioned in readiness for insertion into said first spring.
The method may include the still further step of compressing said first and second springs together, turning said compressed springs through 90xc2x0, feeding said compressed springs into a sleeve of material and forming said compressed springs and a portion of said sleeve of material into a pocketted spring unit.
The method may include the further step of forming said second spring into a pocketted spring prior to said second spring being fed into position for insertion into said first spring.
According to a second aspect of the present invention there is provided a method for the production of a spring unit for use in a mattress, bed, divan bed, or other upholstered unit, the method comprising the steps of forming a first spring in a spring forming machine, feeding a second spring to a composite spring forming station, feeding said first spring to said spring forming station, inserting said second spring within said first spring so as to form a composite spring, compressing said composite spring and turning said composite spring through substantially 90xc2x0, inserting said turned compressed composite spring into a sleeve of material, and forming said compressed composite spring and a portion of said sleeve into a pocketted spring unit.
Preferably, the method will include the additional step of forming said second spring into a pocketted spring prior to it being fed to said composite spring forming station.
According to a third aspect of the present invention there is provided apparatus for forming a spring unit for use in a mattress, bed, divan bed, or other upholstered unit, said apparatus comprising means for feeding a second spring to a composite spring forming station immediately prior to a first spring being fed to said composite spring forming station, means to move said first spring to said composite spring forming station and around said second spring such that the second spring lies within said first spring so as to form a composite spring, and means to form said composite spring into a pocketted spring.
Said means will preferably be a chute or store housing a plurality of second springs, one of said second springs falling from said chute or store and being fed by feeder means into or onto said spring forming station immediately prior to said first spring being fed to said station.
The apparatus will preferably include means to turn the composite spring formed at said spring forming station through 90xc2x0, means to feed said composite spring into a sleeve of material, and means to form said composite spring and a portion of said sleeve into a pocketted spring unit.